Modern farming practices often utilize towable agricultural tillage implements to prepare a seedbed providing optimal conditions for subsequent planting of seed in the seedbed, proper germination and growth of the seed, and conservation of the soil in and below the seedbed. Such implements are configured to provide a seedbed having a number of desirable conditions, including a uniform controlled depth, a flat and smooth floor at the bottom of the seedbed, and a relatively even surface finish.
To cover large acreages as quickly and efficiently as possible, modem towable tillage implements, such as disks and field cultivators, are often very wide, with tillage widths of 22 to 47 feet being common. In order to allow such wide implements to be towed behind a towing vehicle on public roadways, these implements typically are built with frames having a central main frame section and multiple wing sections joined to the main frame by hinged joints, so that the wing sections can be folded up over the main frame section to narrow the width of the implement for transport on public roadways. In addition, the frames of such implements are also intentionally built to allow a limited amount of flexing to occur across the width of the implement during tillage operations, so that tillage tools attached to the frame can better follow variations in the terrain of the ground being tilled.
The hinged joints and inherent flexibility between the main and wing sections of the frame of such implements sometimes leads to undesirable bouncing of the wings, or an undesirable tendency of the outer edges of the tillage tools to dig deeper than desired into the ground surface, particularly while turning or maneuvering around obstacles. The wider the implement, the worse this problem becomes.
In order to counteract the tendency of wide tillage implements to undesirably bounce or dig into the ground surface, some tillage implements utilize so-called stabilizer wheels along outer extremities of the implement. These stabilizer wheels ride on, or close to the ground surface, to damp any bouncing tendencies, and to provide additional support to preclude having the outer ends of the tillage tools dig too deeply into the ground surface during turning or maneuvering the wide tillage implement around obstacles during tillage operations.
Generally speaking, such stabilizer wheels are properly initially adjusted to bear only lightly on the ground surface, until they come into play for reducing bouncing or digging in of the tillage tools. They do not typically function to provide primary support of the implement or primary depth control for the tillage tools. Primary support and depth control are typically provided by support and transport wheels of the implement.
For proper operation of the implement, it is necessary for the stabilizer wheels to be positioned properly with respect to the implement frame, so that the stabilizer wheels can perform their necessary function without interfering with primary depth control and leveling of the tillage tools fore and aft, and across the width of the implement. If the stabilizer wheels are extended too far, or press too hard against the ground surface, the resulting lifting effect on the implement frame will interfere with proper operation of the tillage tools, and seedbed quality will be degraded. As changes are made to the depth of tillage, therefore, the stabilizer wheels must also be adjusted in a corresponding manner to keep the implement operating optimally.
In addition, it may be desirable to retract the stabilizer wheels during certain tillage operations and under certain operating conditions. It is also typically desirable that the stabilizer wheels be retracted prior to and during initial set up and subsequent adjustments to the operating depth and level or trim condition of the tillage tools. Following such set up and adjustments, the stabilizer wheels must be returned to a proper position and degree of ground pressure.
In the past, positioning of stabilizer wheels has typically been accomplished through the use of manually operated turnbuckles or screw jacks, by an operator or an operator's assistant standing on the ground. Alternatively, manually operated hydraulic cylinders have been used to position the stabilizer wheels on some tillage implements. Although hydraulic control cylinders provide advantages over manual turnbuckle approaches, hydraulic systems require bulky hoses, complex valves, and are prone to leakage. Furthermore, they tie up hydraulic circuits of the towing vehicle that could be better utilized for other purposes.
While these prior manual approaches have been successful in the past, they are cumbersome, undesirably time-consuming—particularly where an operator's assistant is needed—and, prone to adjustment error and fluid leakage. Further improvement is desirable.
It is especially desirable to provide an approach to positioning stabilizer wheels that can be carried out remotely by an operator seated in the towing vehicle, without the need for the operator to dismount from the towing vehicle, and without having an assistant on the ground. It is also desirable to provide an approach that allows the stabilizer wheels to be automatically, rather than manually, positioned in response to a simple command from an operator in the cab of the towing vehicle. It is further desirable that the stabilizer wheels be automatically adjusted in response to changes in depth of tillage. It is yet further desirable that an improved approach provide capability for remote, automatic and tillage-depth-responsive adjustment of stabilizer wheel position to be carried out on-the-fly, without the necessity for stopping the towing vehicle, or for the vehicle operator's attention to be diverted from overall operation of the towing vehicle to manually adjust stabilizer wheel position.